Immigration agents broke up a massive marriage fraud ring in Houston that involved nearly 100 people throughout Texas and overseas accused of taking part in sham marriages, officials said.

A federal grand jury in late April indicted 96 defendants on a total of 206 charges relating to mail fraud, marriage fraud, immigration fraud, making false statements under oath, conspiracy to commit those crimes, unlawfully procuring naturalization, obstruction of justice and witness tampering.

"These arrests mark the culmination of a comprehensive year-long multi-agency investigation into one of the largest alleged marriage fraud conspiracies ever documented in the Houston area," ICE special agent in charge Mark Dawson said. "By working together with our partners from various federal law enforcement agencies we have sent a resounding message that we are united in our effort to disrupt and dismantle criminal organizations that seek to circumvent U.S. law by fraudulent means."

The indictment alleges that Ashley Yen Nguyen, 53, ran the false marriage scheme out of Houston with help from associates throughout Texas and in Vietnam, according to an Immigration and Customs Enforcement news release.

The couples would not live together, contrary to what they reported to immigration agencies, and entered the marriage only for financial gain or immigration benefits, an indictment alleges.

A redacted indictment for Nguyen and others alleges the group would charge between $50,000 to $70,000 for each sham marriage depending on what benefits the migrant later received, such as admission to the U.S. and conditional or full permanent resident status.

The fee included additional services such as fake wedding albums to make the marriage appear real and transportation for the couples to the marriage ceremonies and immigration appointments, the indictment states.

The group also allegedly recruited U.S. citizens whom it would pay to enter into the fake unions. Many of the citizens would briefly meet their spouses, while some would be wed without ever meeting. The redacted indictment shows Nguyen herself allegedly entered a sham marriage in September 2016, and others did so in late 2016 and late 2017.

The total time period during which the marriages took place is unclear because of the redactions.

Often, those seeking immigrant benefits would first come to the U.S. on a tourist visa and then get married, the indictment states. Others were already in the U.S. with temporary nonimmigrant status.

Officials have taken 50 people into custody since the indictment was returned on April 30, while the other 46 are listed as fugitives in court records.

Marriage fraud or conspiracy to commit the crime each carry a maximum five-year prison sentence. Mail fraud, conspiracy to commit the same and witness tampering allow up to 20 years in prison. The remaining charges each have maximum 10-year prison terms.